The Green Slime is the titular creature of The Green Slime.
In the future, a giant asteroid heads towards Earth. A team of astronauts is called to plant explosives on it so it can be safely detonated. On the asteroid's surface, however, a small patch of green slime clings to one of the men’s spacesuit and is brought back to the space station. When exposed to the radiation of the decontamination chamber, the slime mutates into a large cyclopean green monster, able to regenerate an entire clone of itself from a single cell and to shoot electric discharges from its tentacles.